4,950 research outputs found
The Non-Relativistic Evolution of GRBs 980703 and 970508: Beaming-Independent Calorimetry
We use the Sedov-Taylor self-similar solution to model the radio emission
from the gamma-ray bursts (GRBs) 980703 and 970508, when the blastwave has
decelerated to non-relativistic velocities. This approach allows us to infer
the energy independent of jet collimation. We find that for GRB 980703 the
kinetic energy at the time of the transition to non-relativistic evolution,
t_NR ~ 40 d, is E_ST ~ (1-6)e51 erg. For GRB 970508 we find E_ST ~ 3e51 erg at
t_NR ~ 100 d, nearly an order of magnitude higher than the energy derived in
Frail, Waxman and Kulkarni (2000). This is due primarily to revised
cosmological parameters and partly to the maximum likelihood fit we use here.
Taking into account radiative losses prior to t_NR, the inferred energies agree
well with those derived from the early, relativistic evolution of the
afterglow. Thus, the analysis presented here provides a robust,
geometry-independent confirmation that the energy scale of cosmological GRBs is
about 5e51 erg, and additionally shows that the central engine in these two
bursts did not produce a significant amount of energy in mildly relativistic
ejecta at late time. Furthermore, a comparison to the prompt energy release
reveals a wide dispersion in the gamma-ray efficiency, strengthening our
growing understanding that E_gamma is a not a reliable proxy for the total
energy.Comment: Submitted to ApJ; 13 pages, 6 figures, 1 table; high-resolution
figures can be found at: http://www.astro.caltech.edu/~ejb/NR
ROLE OF PLACEBO AND PSYCHOLOGICAL COUNSELING IN THE MANAGEMENT OF SHUKRAGAT VATA W.S.R. TO PREMATURE EJACULATION
Premature Ejaculation is very common male sexual disorder. Anxiety, Stress, Fear etc. are the main etiological factor of premature ejaculation. In Ayurveda, this condition can be correlated with Shukragat Vata. In this clinical trial management is done by Placebo with psychological counseling. Placebo (starch powder) is given 6 gm. two times a day with Koshna jal (warm water) as a Anupana in 20 patients. Placebo with psychological counseling was found to be effective to a certain extent in the management of Shukragat Vata (premature ejaculation). This study was conducted on 23 patients with statistically highly significant result (p<0.001) on the chief complaints of Premature Ejaculation
Investigation of laser ablated ZnO thin films grown with Zn metal target: a structural study
High quality ZnO thin films were gown using the pulsed laser deposition
technique on (0001) AlO substrates in an oxidizing atmosphere, using a
Zn metallic target. We varied the growth conditions such as the deposition
temperature and the oxygen pressure. First, using a battery of techniques such
as x-rays diffraction, Rutherford Backscattering spectroscopy and atomic force
microscopy, we evaluated the structural quality, the stress and the degree of
epitaxy of the films. Second, the relations between the deposition conditions
and the structural properties, that are directly related to the nature of the
thin films, are discussed qualitatively. Finally, a number of issues on how to
get good-quality ZnO films are addressed.Comment: To be published in Jour. Appl. Phys. (15 August 2004
Simulations of Oligomeric Intermediates in Prion Diseases
We extend our previous stochastic cellular automata based model for areal
aggregation of prion proteins on neuronal surfaces. The new anisotropic model
allow us to simulate both strong beta-sheet and weaker attachment bonds between
proteins. Constraining binding directions allows us to generate aggregate
structures with the hexagonal lattice symmetry found in recently observed in
vitro experiments. We argue that these constraints on rules may correspond to
underlying steric constraints on the aggregation process. We find that monomer
dominated growth of the areal aggregate is too slow to account for some
observed doubling time-to-incubation time ratios inferred from data, and so
consider aggregation dominated by relatively stable but non-infectious
oligomeric intermediates. We compare a kinetic theory analysis of oligomeric
aggregation to spatially explicit simulations of the process. We find that with
suitable rules for misfolding of oligomers, possibly due to water exclusion by
the surrounding aggregate, the resulting oligomeric aggregation model maps onto
our previous monomer aggregation model. Therefore it can produce some of the
same attractive features for the description of prion incubation time data. We
propose experiments to test the oligomeric aggregation model.Comment: 8 pages, 10 figures For larger versions of several figures, see
http://asaph.ucdavis.edu/~dmobley and click on the prion paper lin
Influence of catalyst deactivation on the nature of the steady state solutions for reactions on catalytic surfaces
This article does not have an abstract
Evidence for a quantum phase transition in the electron-doped cuprate Pr2-xCexCuO4+d from Hall and resistivity measurements
The doping and temperature dependence of the Hall coefficient, RH, and
ab-plane resistivity in the normal state down to 350mK is reported for oriented
films of the electron-doped high-Tc superconductor Pr2-xCexCuO4+d. The doping
dependence of b (r=r0+AT^b) and R_sub_H (at 350 mK) suggest a quantum phase
transition at a critical doping near x=0.165.Comment: 11 pages 4 figures Phys. Rev. Lett. 92, 167001 (2004
A 450-day light curve of the radio afterglow of GRB 970508: Fireball calorimetry
We report on the results of an extensive monitoring campaign of the radio
afterglow of GRB 970508, lasting 450 days after the burst. The spectral and
temporal radio behavior indicate that the fireball has undergone a transition
to sub-relativistic expansion at t~100 days. This allows us to perform
"calorimetry" of the explosion. The derived total energy, ~5\times 10^{50} erg,
is well below the ~5\times 10^{51} erg inferred under the assumption of
spherical symmetry from gamma-ray and early afterglow observations. A natural
consequence of this result, which can also account for deviations at t<100 days
from the spherical relativistic fireball model predictions, is that the
fireball was initially a wide-angle jet of opening angle ~30 degrees.
Our analysis also allows to determine the energy fractions carried by
electrons and magnetic field, and the density of ambient medium surrounding the
fireball. We find that during the sub-relativistic expansion electrons and
magnetic field are close to equipartition, and that the density of the ambient
medium is ~1/cm^3. The inferred density rules out the possibility that the
fireball expands into a strongly non-uniform medium, as would be expected,
e.g., in the case of a massive star progenitor.Comment: 33 pages, including 7 figures, submitted to Ap
Collective behavior of stock price movements in an emerging market
To investigate the universality of the structure of interactions in different
markets, we analyze the cross-correlation matrix C of stock price fluctuations
in the National Stock Exchange (NSE) of India. We find that this emerging
market exhibits strong correlations in the movement of stock prices compared to
developed markets, such as the New York Stock Exchange (NYSE). This is shown to
be due to the dominant influence of a common market mode on the stock prices.
By comparison, interactions between related stocks, e.g., those belonging to
the same business sector, are much weaker. This lack of distinct sector
identity in emerging markets is explicitly shown by reconstructing the network
of mutually interacting stocks. Spectral analysis of C for NSE reveals that,
the few largest eigenvalues deviate from the bulk of the spectrum predicted by
random matrix theory, but they are far fewer in number compared to, e.g., NYSE.
We show this to be due to the relative weakness of intra-sector interactions
between stocks, compared to the market mode, by modeling stock price dynamics
with a two-factor model. Our results suggest that the emergence of an internal
structure comprising multiple groups of strongly coupled components is a
signature of market development.Comment: 10 pages, 10 figure
EFFICACY OF SHIVA GUTIKA WITH SARASWATARISHTA IN THE MANAGEMENT OF AGE ASSOCIATED MILD COGNITIVE IMPAIRMENT (AAMCI)
Objective: To find the efficacy of Shiva gutika with Saraswatarishta in management of Age Associated Mild Cognitive Impairment (AAMCI). To review the literature of mild cognitive impairment, Jara, and aging as per modern science and Ayurveda. To observe side effects of the drug if any. To access effect of drug on other signs and symptoms of Jara.Method: Open Trial study was conducted on 25 patients having AAMCI and were selected for the study randomly. The patients received 1gm Shiva gutika once a day with 40ml Saraswatarista as Anupan for 3 months.Assessment Criteria: Improvement in all the six cerebral higher functions on the basis of various tests such as MMSE, CAMCOG (CAMDEX), ADL/IADL, GDS.Follow up: 0, 15th, 30th, 45th, 60th, 75th, 90th day.Duration: Total duration study was 90 Days. This study was carried out in Bharati Vidyapeeth Deemed University College of Ayurved & Hospital Pune in Year 2010 and 2011.Results: Comparing all the symptoms before and after treatment had significant action in age associated mild cognitive impairment (AAMCI). No side effects of the drug during clinical trial were seen.Statistical Analysis: The Statistical Analysis reveals that Shiva gutika with Saraswatarista as Anupan effective in age associated mild cognitive impairment (AAMCI).Conclusion: Shiva gutika with Saraswatarista shared significant results in AAMCI. The overall effect of drug on ADL & IADL showed significant result
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